Vertical Oxide Transistor Shielding for Low Off Current
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Solution Overview
Problem
Conventional semiconductor materials used in vertical transistors exhibit high off current and are sensitive to hydrogen-containing etch chemistries, leading to degraded electrical properties and low threshold voltage, which affects charge retention and switching speed.
Innovation Solution
The semiconductor device incorporates vertically oriented channel regions with a gate electrode surrounded by a gate dielectric material, where the gate electrode is centrally located between the channel regions, and an electrically conductive shielding material is used to reduce word line disturb and capacitance, allowing for improved hydrogen tolerance and faster switching speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional semiconductor materials are used in vertical transistors, then the transistor structure can be formed, but the off current becomes high and electrical properties degrade
Solution Approach 1:
The patent changes the material parameter from conventional semiconductor materials to hydrogen-tolerant semiconductor materials, which fundamentally alters the electrical characteristics by reducing off current and improving threshold voltage stability against hydrogen exposure
Solution Approach 2:
The patent employs composite material structures including hydrogen-tolerant semiconductor channel materials combined with specific gate dielectric materials and shielding layers, creating a multi-material system that collectively resists hydrogen degradation and maintains electrical performance
2Ease of manufacture
If hydrogen-containing etch chemistries are used to form pillars, then the semiconductor material can be patterned, but the electrical properties degrade and threshold voltage decreases
Solution Approach 1:
The patent introduces shielding materials as intermediary layers between the hydrogen-containing etch environment and the semiconductor channel material, protecting the channel from hydrogen exposure while allowing the etch process to proceed
Solution Approach 2:
The patent changes the chemical resistance parameter of the semiconductor material by selecting hydrogen-tolerant materials that maintain their electrical properties even when exposed to hydrogen-containing etch chemistries
3Ease of operation
If conventional vertical transistor configuration is used, then the basic transistor function is achieved, but word line disturb and capacitance are high
Solution Approach 1:
The patent introduces electrically conductive shielding material as an intermediary component between adjacent vertical transistors, which acts as a shield to reduce capacitive coupling and word line disturb while maintaining the basic transistor operation
Data Source
AI summary
A device comprises a vertical transistor and a shielding material comprising a conductive material having a P+ type conductivity. The vertical transistor includes an electrode, a dielectric material adjacent to the electrode, and a channel region adjacent to the dielectric material. The channel region comprises a composite structure including at least two semiconductor materials. Also disclosed is a device comprising a first electrically conductive line, vertical transistors overlying the first conductive line, a second electrically conductive line overlying the vertical transistors, and a shielding material positioned between the two adjacent vertical transistors. Each of the vertical transistors comprises a gate electrode, a gate dielectric material on opposite sides of the gate electrode, and a channel region comprising a composite structure including at least two oxide semiconductor materials. The gate dielectric material positions between the gate electrode and the channel region. The shielding material comprises an electrically conductive material.